It is well known in the art to chemically remove or otherwise strip cured coatings of paint, varnish or the like by treating the coated surface with a composition that includes volatile chlorinated hydrocarbons, such as methylene chloride, or N-methyl-2-pyrrolidone, a nitrogen heterocyclic compound. However, the use of such products presents problems for the environment and such formulations are based on suspected carcinogens.
Furthermore, paint removal systems have been developed which are designed to remove multiple layers of paint in only one application for easy removal and control of stripped paint thus preventing particles of lead and other toxic compounds from polluting the atmosphere. Essentially these rely on the application of a membrane over the applied patent stripper to assist in the penetration of the paint stripper into the several layers of paint and subsequent removal thereof by the virtue of the treated paint layers adhering to the membrane for easy removal.
For example, U.S. Pat. No. 4,579,627 to Michael I Brailsford, the applicant for the present invention, describes the use of a needle punched polypropylene as such a membrane. However that material was not impermeable and was found to be less effective than materials now put forward in this specification.
A second patent, in the name of the same inventor, GB. 2,337,759 describes a low-density polyethylene laminated to a paper tissue, in which the polyethylene was impermeable but not biodegradable. This material however provided improvements in allowing the stripper to penetrate the layers of paint more effectively but suffered in being difficult to dispose of.
Whilst these systems were relatively effective in removing layers of paint in one application, they were not ecologically compatible in that they did not provide a degradable or biodegradable membrane, nor were the paint stripping formulae themselves safe for the environment. Therefore, although removal of the paint from the substrate was effective, subsequent disposal of the membrane/removed paint/used stripper was problematic.